Phenolic constituents,antioxidant and antimicrobial activities of rosy garlic (Allium roseum var. odoratissimum)

The methanol extracts of leaves, flowers, stalks and bulbs of the North African endemic Allium roseum var. odoratissimum were analyzed for their phenolic profiles and screened for their antioxidant and antibacterial activities. Colourimetric analysis revealed that the highest levels of total phenols content (TPC) and total flavonoids content (TFC) were found in the flowers and leaves. The use of HPLC-PDA-MS allowed the identification of kaempferol 3,7-di-O-rhamnoside, kaempferol-3-Glucuronide, kaempferol-3-O-glucoside, kaempferol-3-O-beta-d-glucoside-7-O-alpha-l-rhamnoside, luteoline and apigenine, while four components remained unidentified. The flowers and leaves were found to possess the highest antioxidant activity with the exception in metal chelating ability. Antibacterial assay showed that Enterococcus feacium was the most susceptible bacterial strain and the stalk extract had the most effect in the inactivation of Staphylococcus aureus, Enterococcus feacium, Bacillus subtilis and Escherichia coli. Conclusively, this study allows a clear chemical differentiation between A. roseum var. odoratissimum and the other Allium species.     

Composition of organosulfur compounds from cool- and warm-type garlic (Allium sativum L.) in Korea

The organosulfur and degradation compounds of cool- and warm-type garlic were analyzed in Korea. This garlic exhibited a wide range of organosulfur compound levels. Analytical results indicated large amounts of alliin, γ-glutamyl-S-allyl-l-cysteine (GSAC) and γ-glutamyl-S-trans-1-propenyl-l-cysteine (GSPC) in garlic. The contents of alliin, GSAC, and GSPC were in the range of 10.52–30.12, 11.46–26.45, and 9.15–41.66 mg/g garlic (dry base), respectively. Allicin was the major biological compound at 2.53–9.36mg/g (dry base). GC/MS was employed to identify allicin degradation compounds in fresh garlic. The major chemical components of fresh garlic were diallyl sulfides and methyl allyl sulfides. Differences in the pattern of organosulfur composition and degradation components of thiosulfinates from warm- and cool-type garlic were demonstrated by principle component analysis. Therefore, the results may be useful for the quality evaluation of cool- and warm-type garlic in Korea.     

Biologically active substances in garlic (Allium sativum L.) and their application in nutrition for humans

Reviewed above is chemical composition of garlic and its biological Hypolipidemic, antioxidative, antibacterial and antitumorogenic properties of preparations were elucidated in experimental, clinical and epidemiological observations. It has been concluded that garlic are useful for prevention and combined treatment of most chronical diseases.     

Influence of sulphate nutrition on the flavour components of garlic (Allium sativum) and wild onion (A. vineale)

Investigation of the relationship between the sulphate nutrition of garlic (Allium sativum) and wild onion(A. vineale) and their flavour strength is now reported. The plants were grown in a glasshouse in sand culture at two concentrations of sulphate in the nutrient medium and their flavour strength determined by sensory, biochemical and gas chromatographic methods. These observations have furnished further examples of environmental control of flavour components. The garlic plants in the two groups differed significantly in their fresh weights per plant. Their sulphur contents also showed that deficiency of this nutrient had been established in spite of the relatively large amount of sulphur introduced in the original cloves. The ratios of total sulphur content in the two groups of plants and of their flavour strengths as determined by total pyruvate values and taste threshold concentrations, respectively, were approximately constant (about 5). Total peak areas in the gas chromatograms increased with increasing (sensory) flavour strength. The garlic plants grown in sand culture were morphologically atypical, possibly because of the high moisture content of the growth medium, but their odour, taste and gas chromatograms were qualitatively indistinguishable from those of field-grown garlic which grew normally. Similar but more pronounced differences of flavour strengths were obtained with A. vineale and in this case the difference in flavour strengths between the deficient and normal plants was about 13-fold. The gas chromatograms of the deficient plants were almost completely lacking in the peaks which are characteristic of Allium sp. The discrepancies between initial and final sulphur contents of the deficient plants are discussed.     

Bioactive compounds,in vitro antioxidant capacity and Maillard reaction products of raw,boiled and fried garlic (Allium sativum L.)

Garlic is used in many dishes but some of its bioactive compounds are lost when exposed to heat. This study evaluated bioactive compounds, antioxidant activity and Maillard reaction products of raw (RG), boiled (BG) and fried garlic (FG). Total phenolic compounds, flavonoids, allicin and phytosterol were quantified as well as dietary fibres and mineral content. Antioxidant activities of RG, BG and FG were evaluated by oxygen radical absorbance capacity (ORAC), oxidation of β‐carotene/linoleic acid and Rancimat methods. The main results were the following: thermal processing of RG decreased both bioactive compounds and antioxidant capacity, boiling was found to be less aggressive than frying, and strong correlations were obtained between total phenolic compounds and the antioxidant assays. However, phytosterol content was higher in FG than in RG and BG and higher temperatures increased the formation of Maillard reaction products. It was concluded that RG and BG should be preferred for human consumption as they present higher antioxidant capacity.     

不同溶剂提取对洋葱皮中多酚含量及抗氧化活性的影响

为有效利用废弃的洋葱外皮,以丙酮、甲醇、乙醇和水为溶剂,提取不同品种洋葱皮中的总酚和总黄酮物质,了解他们的含量及抗氧化活性的差异。选用体积分数为70%的丙酮、70%甲醇、70%乙醇和水分别提取红、白、黄3种颜色的洋葱皮,测其表皮中总酚、总黄酮含量。通过测定1,1-二苯基-2-苦肼基(2,2-diphenyl-1-1picrydrazyl,DPPH)自由基清除能力、三价铁还原能力(ferric reducing abilbity of plasma,FRAP)、2,2'-联氨-二-3-基-苯并噻唑-6-磺酸(2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate,ABTS)自由基清除能力,评价其体外抗氧化能力差异。结果显示,紫洋葱皮中抗氧化物质含量和抗氧化能力均显著高于黄、白洋葱皮。70%丙酮提取液中,总酚、总黄酮含量最高,体外抗氧化能力最高,且洋葱皮中总酚对抗氧化能力的贡献高于总黄酮。     

UV-B-induced changes of volatile metabolites and phenolic compounds in blueberries (Vaccinium corymbosum L.)

There are many reports on the potential consequences of UV-B radiation on plants, but there is a rather limited understanding of the effect on secondary plant metabolites, e.g. phenolic compounds and volatiles, at all. The popularity of highbush blueberries (Vaccinium corymbosum L.) is mainly due to its unique flavour and its high content of bioactive compounds, i.e. phenolic compounds. However, information on UV-B elicitor mediated changes on secondary plant metabolites on blueberries is scanty. In the present study, blueberry fruits were harvested and exposed to UV-B radiation with different dosage and adaptation times. With regard to volatile secondary metabolites, C₆-aldehydes, terpenes and ketones, an increase of the relative peak area was observed after both UV-B treatments (0.075 and 0.15 Wh/m² = low [L] and high [H] dosage, respectively). Furthermore, there was a strong influence of the adaptation time. Increasing relative peak areas were determined already after a short adaptation time (2 h) at both, low and high UV-B dosages, but after 24 h adaptation time relative peak areas decreased significantly. However, alcoholic compounds, as degradation products of aldehydes, showed opposite results. In contrast, the non-volatile phenolic compounds revealed a continuously increase with UV-B intensity.     

Garlic (Allium sativum L.): adverse effects and drug interactions in humans

Garlic (Alllium sativum L., Fam Liliaceae) is used medicinally mainly for the treatment of hypercholesterolemia and prevention of arteriosclerosis. Clinical trials have consistently shown that "garlic breath" and body odor are the most common (and well-documented) complaints associated to garlic intake. Case reports have highlighted the possibility that garlic use may cause allergic reactions (allergic contact dermatitis, generalized urticaria, angiedema, pemphigus, anaphylaxis and photoallergy), alteration of platelet function and coagulation (with a possible risk of bleeding), and burns (when fresh garlic is applied on the skin, particularly under occlusive dressings). Consumption of garlic by nursing mothers modifies their infant's behavior during breast-feeding. Finally, garlic may enhance the pharmacological effect of anticoagulants (e. g. warfarin, fluindione) and reduce the efficacy of anti-AIDS drugs (i. e. saquinavir).     

Traditional and modern uses of onion bulb (Allium cepa L.): a systematic review

Abstract

Onion, (Allium cepa L.), is one of the most consumed and grown vegetable crops in the world. Onion bulb, with its characteristic flavor, is the third most essential horticultural spice with a substantial commercial value. Apart from its culinary virtues, A. cepa is also used traditionally for its medicinal virtues in a plethora of indigenous cultures. Several publications have been produced in an endeavor to validate such traditional claims. Nonetheless, there is still a dearth of up-to-date, detailed compilation, and critical analysis of the traditional and ethnopharmacological propensities of A. cepa. The present review, therefore, aims to systematically review published literature on the traditional uses, pharmacological properties, and phytochemical composition of A. cepa. A. cepa was found to possess a panoply of bioactive compounds and numerous pharmacological properties, including antimicrobial, antioxidant, analgesic, anti-inflammatory, anti-diabetic, hypolipidemic, anti-hypertensive, and immunoprotective effects. Although a large number of in vitro and in vivo studies have been conducted, several limitations and research gaps have been identified which need to be addressed in future studies.     

Uptake of arsenic species by turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) treated with roxarsone and its metabolites in chicken manure

Roxarsone is an organoarsenic feed additive that can be metabolised to other higher toxic arsenic (As) species in animal manure such as arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, 3-amino-4-hydroxyphenylarsonic acid and other unknown As species. The accumulation, transport and distribution of As species in turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) amended with roxarsone and its metabolites in chicken manure were investigated. Results showed arsenite was the predominant As form, followed by arsenate in turnip and lettuce plants, and a low content of dimethylarsinic acid was detected only in lettuce roots. Compared with the control plants treated with chicken manure without roxarsone and its metabolites, the treatments containing roxarsone and its metabolites increased arsenite content by 2.0–3.2% in turnip shoots, by 6.6–6.7% in lettuce shoots, by 11–44% in turnip tubers and by 18–20% in lettuce roots at two growth stages. The enhanced proportion of arsenate content in turnip shoots, turnip tubers and lettuce roots was 4.3–14%, 20–35% and 70%, respectively, while dimethylarsinic acid content in lettuce roots increased 2.4 times. Results showed that the occurrence of dimethylarsinic acid in lettuce roots might be converted from the inorganic As species and the uptake of both inorganic and organic As compounds in turnip and lettuce plants would be enhanced by roxarsone and its metabolites in chicken manure. The pathway of roxarsone metabolites introduced into the human body via roxarsone → animal → manure → soil → crop was indicated.     

Influence of alcoholic fermentation process on antioxidant activity and phenolic levels from mulberries (Morus nigra L.)

The aim of the present study was to evaluate the profile of the phenolic constituents of Morus nigra fruits and their antioxidant activity (DPPH) and to compare their contents before and after fermentation. Antioxidant phenolics of black mulberry (M. nigra L.) samples grown in Galicia (NW Spain) were extracted with methanol/formic acid/water (MFW) and determined by high performance liquid chromatography (HPLC). Two major anthocyanins (cyanidin 3-glucoside and cyanidin 3-rutinoside) and two flavonols (quercetin 3-glucoside and rutin) were isolated, together with caffeic acid and other hydroxycinnamic and ellagic acid derivatives. Their chemical structures were identified by spectral analyses with diode array detection (DAD), but also with alkaline saponification and acid hydrolysis of the mulberry phenolics. Good correlations (r² = 0.6229) were observed among total flavonols contents and the IC₅₀ radical scavenging capacities of mulberry fruits. Anthocyanins are the major flavonoids present in mulberry. It would be expected that anthocyanins contribute significantly to their antioxidant activity; nevertheless, alcohol generated during fermentation may also contribute to antioxidant activity. Our results provide useful antioxidant nutritional information of fresh and fermented mulberry fruits.     

Effect of germination on vitamin C,phenolic compounds and antioxidant activity in flaxseed (Linum usitatissimum L.)

Flaxseed (Linum usitatissimum L.) is well known for its health benefits and chemical composition. This study aimed to evaluate the dynamic changes caused by germination in vitamin C, phenolic compounds and antioxidant activities of flaxseed. It was observed that eight‐day germination of flaxseed sprouts caused increases in phytochemical contents, that is 22.1‐fold increase in vitamin C, 2.67‐fold increase in phenolics and 5.48‐fold increase in flavonoid contents as compare to initial concentration in flaxseeds on dry weight basis. The stimulation was also noted in the three identified phenolic acid ingredients including caffeic acid, p‐coumaric acid and ferulic acid. Similarly, the total PSC and ORAC values of flax sprouts at day 8 increased by 3‐ to 4‐folds compared to nongerminated flaxseeds. It is revealed that comparatively, 8‐day germination of flax sprouts leads to a significant increase in vitamin C, phenolic constituents and total antioxidant activities than those of flaxseeds.     

Green pigment in crushed garlic (Allium sativum L.) cloves: Purification and partial characterization

Unknown green pigment, responsible for greening in crushed garlic cloves, was purified and characterized by using a series of column chromatography, liquid chromatography–electrospray ionization (LC–ESI), fast atom bombardment (FAB), matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy. The purified green pigment was highly polar and slightly viscous, with a garlic flavor, and easily turned to a yellow or brown color with exposure to room temperature. The absorption spectrum in methanol showed a crude methanolic green pigment-like profile with two absorbance maxima at 440 and 590 nm.     

Effect of Callosobruchus chinensis (L.) (Coleoptera: Bruchidae) on carbohydrate content of chickpea,green gram and pigeon pea

Effect of Callosobruchus chinensis (L.) infestation was seen on the carbohydrate and dietary fibre content of chickpea, green gram and pigeon pea at 10, 20, 30, 40, 50 and 60 per cent levels of infestation. With increase in level of infestation energy, starch, total sugars and non-reducing sugars decreased, whereas significant increase in the reducing sugars, crude fibre, neutral detergent fibre, acid detergent fibre, hemicellulose, cellulose and lignin was observed.     

Polyphenol oxidase activity,phenolic acid composition and browning in cashew apple (Anacardium occidentale, L.) after processing

This study describes the extraction and characterisation of cashew apple polyphenol oxidase (PPO) and the effect of wounding on cashew apple phenolic acid composition, PPO activity and fruit browning. Purification factor was 59 at 95% (NH₄)₂SO₄ saturation. For PPO activity, the optimal substrate was catechol and the optimum pH was 6.5. PPO K_m and V_max values were 18.8 mM and 13.6 U min⁻¹ ml⁻¹, respectively. Ascorbic acid, citric acid, sodium sulphite and sodium metabisulphite decreased PPO activity, while sodium chloride increased PPO activity. Wounding at 2 °C and 27 °C for 24 h increased PPO activity but storage at 40 °C reduced PPO activity. Gallic acid, protocatechuic acid and cinnamic acid (free and conjugate) were identified in cashew apple juice. Cutting and subsequent storage at 40 °C hydrolysed cinnamic acid. 5-Hydroxymethylfurfural content in cashew apple juice increased after injury and storage at higher temperatures, indicating non-enzymatic browning.     

Impact of edible coatings and packaging on quality of white asparagus (Asparagus officinalis, L.) during cold storage

The effects of edible coatings and plastic packaging on quality aspects of refrigerated white asparagus spears were studied using two different experimental protocols. The first included four coating formulations based on carboxymethyl-cellulose and sucrose fatty acid esters, whey protein isolate alone and in combination with stearic acid, and pullulan and sucrose fatty acid esters, and an uncoated sample serving as a control. The second set consisted of four treatments; uncoated asparagus spears (control), coated with a carboxymethyl-cellulose formulation, packaged in plastic packaging and combination of coated and packaged asparagus spears. All products were stored at 4 °C and the quality parameters such as weight loss, texture, visual appearance, lignin and anthocyanins concentration, and colour were evaluated during their storage. Edible coatings exhibited a beneficial impact on the quality of asparagus by retarding moisture loss, reducing hardening in their basal part and slowing down the purple colour development. The plastic packaging had a remarkable influence in reducing weight loss and retarding hardening but its impact to the rest of the quality parameters was similar to that of the edible coatings. The combination of packaging and edible coating did not seem to offer any additional advantage on asparagus spears apart from the fact that the product had a brighter appearance at the middle part of the stem compared to the packaged spears alone.     

Influence of origin source, different fruit tissue and juice extraction methods on anthocyanin, phenolic acid, hydrolysable tannin and isolariciresinol contents of pomegranate (Punica granatum L.) fruits and juices

To gain more comprehensive knowledge of pomegranate (Punica granatum L.) fruit composition and its impact on juice features, fruits and juices produced from fruits of eleven different provenances were investigated by HPLC–DAD-ESI/MSⁿ for their monomeric phenolic and lignan profiles. Total phenolics and antioxidant capacity were monitored by the Folin-Ciocalteu, ferric reducing antioxidative power and Trolox equivalent antioxidant capacity assays. Peels, mesocarp, seeds and juices obtained from isolated arils (PJAs) as well as from entire fruits were separately analyzed. Ellagitannins were found to be the predominant phenolics in all samples except in PJAs. However, due to the low lignan amounts, only isolariciresinol could be quantitated in peels and mesocarp. The peels and mesocarp revealed highest contents of hydrolyzable tannins (27–172 g/kg and 32–263 g/kg, respectively) and isolariciresinol (4.9–19.8 mg/kg and 5.0–13.6 mg/kg, respectively). To the best of our knowledge, a systematic investigation of monomeric phenolic compounds and isolariciresinol considering diverse pomegranate fruits has been performed for the first time. The study demonstrates that raw material and extraction process have significant impact on juice composition and thus must be carefully selected. Furthermore, pomegranate processors should select juice extraction processes according to the final designation of the product, that is, distinguish between dietary products being rich in phenolic compounds having an astringent taste, and juices for consumption having an appealing taste but lower amounts of phenolics, respectively. This study may further contribute to facilitate authenticity control of diverse pomegranate products and help predict sensory and biofunctional characteristics of pomegranate juices.